Determination of remote control operator position

ABSTRACT

A system and method for controlling a work machine system having a work machine and work tool. Operational characteristics of both the work machine and work tool are configured by a machine controller based upon the type of work tool attached to the work machine, the operating environment of the work machine, and the location of work site personnel or other observers relative to the machine or work tool. The operational characteristics of both the work machine and work tool may then be automatically altered during operation of the work machine system to limit or expand functions of the work machine system in response to changes in the operational environment or movement of personnel or observers relative to the work machine system.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/441,690, filed May 26, 20006, which claims the benefit of U.S.Provisional Application No. 60/685,744 filed May 27, 2005, the contentsof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the operation of a workmachine and in particular to controlling operation and movement of thework machine based upon the position of an operator or observer relativeto the work machine.

SUMMARY OF THE INVENTION

The present invention is directed to a method for controlling a workmachine comprising a work tool. The method comprises determining a typeof work tool operatively connected to the work machine and loadingoperational characteristics of the work machine and the work tool basedupon the type of work tool operatively connected to the work machine. Anoperational boundary defined by the type of work tool and configurationof the work machine is established. The location of a person relative tothe operational boundary is determined and an operational characteristicof the work tool or work machine is automatically altered based upon thelocation of the person relative to the operational boundary.

The present invention further includes a method for controllingoperation of a work machine system. The work machine system comprises amovable work machine and a work tool. The method comprises determiningan operating condition of the work machine system and loading at leastone operational characteristic of the work tool and the work machinebased upon the type of work tool and the operating condition of the workmachine system. A location of a person relative to the work machine isdetermined and at least one operational characteristic of the work toolis altered based upon the location of the person relative to the workmachine.

The present invention is also directed to a system for controllingoperation of a work machine having a work tool. The system comprises anattachment sensor, a controller assembly, an antenna assembly, and aprocessing assembly. The attachment sensor determines attachment of thework tool and the type of work tool operatively connected to the workmachine. The controller assembly is supported by the work machine togenerate control signals used for operation of the work machine and thework tool. The antenna assembly is supported by the work machine toestablish an operational boundary around the work machine and work tooland to transmit a personnel detection signal. The processing assemblyconfigures the controller assembly for operation of the work tooldetected by the attachment sensor, determines a location of personnelrelative to the operational boundary and periodically alters the controlsignal output by the controller system to change an operationalcharacteristic of the work tool based upon a detected location ofpersonnel relative to the operational boundary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic representation of a remote controlled workmachine constructed in accordance with the present invention. FIG. 1shows an operator using a remote controller to control operationalcharacteristics of the work machine and a work tool supported thereon.

FIG. 2 is an overhead view of the remote controlled work machine shownin FIG. 1. FIG. 2 illustrates the use of operational sectors to controlor alter the operational characteristics of the work machine based uponthe location of the operator within a certain operational sector.

FIG. 3 is an overhead view of the remote controlled work machine of FIG.2 showing the operational sectors shifted to comprise front, back, left,and right sectors.

FIG. 4 is a perspective view of a gimble-mounted transmitter/receiverassembly adapted to transmit a scanning machine signal to determine thelocation of the operator relative to the work machine.

FIG. 5 is an overhead view of a remote controlled work machine depictingthe use of a plurality of transmitters or receiver supported by themachine to utilize “beacon-tracker” technology to determine the locationof the operator.

FIG. 6 is a perspective view of a receiving assembly of the presentinvention suitable for use with the beacon-tracker system of FIG. 5.

FIG. 7 is a block diagram of a remote control system capable of locatingthe position of the remote control operator.

FIG. 8 is a flow chart illustrating a process for locating the relativeposition of a remote controller with respect to the work machine beingcontrolled, then altering or controlling certain machine operationswhenever a threshold clearance zone is breached.

FIG. 9 is a continuation of the flow chart of FIG. 8, showing a processfor detecting the location of any authorized workers or observers withinthe operational boundary of the work machine.

DESCRIPTION OF THE INVENTION

The invention of the present application provides a method and apparatusdirected to reducing worksite accidents by altering or controlling anoperational characteristic of either or both a work machine and worktool based upon the position of a remote operator and/or the position ofa member of the work crew, relative to the work machine.

Turning to the figures and more specifically to FIG. 1, there is showntherein a system for controlling operation of a work machine 10. Thesystem shown in FIG. 1 comprises a work machine 10 and a remotecontroller 12 used to control the work machine from a remote location.The work machine 10 shown in FIG. 1 comprises a small loader with atrack-laying undercarriage 14. Such a work machine 10 belongs to the“tool carrier” class of machines frequently utilized on construction andearthmoving work sites. The “tool carrier” classification implies thatthe work machine 10 is adaptable to a variety of tasks throughinterchangeable work tools 16 comprising a plurality of operationalcharacteristics controlled in response to a control signal 18 from theremote controller 12. For purposes of illustration, the work tool 16shown in FIG. 1 comprises a front-end loader bucket attachable to amovable arm 20 or other positioning mechanism. A wide variety of workmachines 10 can be classified as tool carriers, including skid steerloaders and compact excavators. One skilled in the art will appreciatethat a wide variety of work machines 10 may be remotely controlled inaccordance with the present invention.

The work machine 10 may comprise a controller assembly 22 supported bythe work machine and comprise a receiver assembly 24 and a processor(not shown). The receiving assembly 24 may comprise a bi-directionalcommunication system for communicating with the remote controller 12 anda Global Positioning Satellite (“GPS”) receiver 26 adapted to receivesignals 42 from a plurality of GPS satellites 28. The receiving assembly24 is adapted to detect the control signals 18 from the remotecontroller 12. These control signals 18 are used to control or alter avariety of work machine 10 operational characteristics. Control signals18 are detected by the receiving assembly 24 and processed by theprocessor (not shown) to determine a location of an operator 30 carryingthe remote controller 12. Additionally, the processor uses the detectedsignals to change or alter an operational characteristic of the workmachine 10 based upon the location of the operator 30 in relation to thework machine or based upon the control signal 18 from the remotecontroller 12 in a manner yet to be described. In addition to the signalreceiving assembly 24, the controller assembly 22 may comprise a machinetransmitter assembly (not shown) adapted to transmit machine signals(discussed hereinafter) to the signal system of the remote controller12. Such work machine operation information may comprise currentoperational status of the work machine 10.

The remote controller 12 may comprise a portable frame 32 that can beworn or carried by an operator 30, a signal system having a signalgenerator (not shown), and at least one user input device 34. The signalsystem comprises a signal generator adapted to generate the previouslydiscussed control signal 18. One skilled in the art will appreciate thatseveral commercially available signal generators would be appropriatefor the purpose of generating the control signal 18. For example, thesignal generator may comprise an ultrasonic signal generator adapted totransmit an ultrasonic control signal 18. The control signal 18 mayserve a wide variety of uses such as communicating a control command tothe controller assembly 22 or for determining the location of the remotecontroller 12 relative to the work machine 10. Additionally, the remotecontroller 12 may comprise a GPS receiving antenna 36 that may be usedin cooperation with the work machine GPS receiving antenna 26 todetermine the location of the remote controller 12 relative to the workmachine 10.

Continuing with FIG. 1, the operator 30 remotely controls the workmachine 10 and work tool 16 by activating at least one user input device34 adapted to generate the control command for communication to thecontroller assembly 22. The user input devices 34 may comprise switches,joysticks, or other input devices regularly used on known remote controlsystems. Additionally, the user input device 34 may comprise a systemfor controlling the work machine 10 in response to voice commands.Although wireless remote control is preferred, one skilled in the artwill appreciate that a wired cable may be used for bi-directionalcommunication between the remote controller 12 and the work machine 10.

In addition to the control signal 18 transmitted by the remotecontroller 12, each authorized worker may have an “identifier”, such asa Radio Frequency Identification (“RFID”) tag or reflector 38 to allowthe system to detect and track multiple personnel in the local work areaaround the machine 10. The “identifier” or “tag” 38 may be worn on theperson and can be made individually unique. For example, in its responseto being impinged by the machine signal, the identifier 38 may send acertain characteristic return radio frequency signal to the receivingassembly 24. Accordingly, the machine controller 22 of the receivingassembly 24 has knowledge of the number of authorized persons present inthe work area and can adjust itself to track each person. When anidentifier 38 is worn by the operator 30 instead of (or in addition to)being mounted to the remote controller 12, its particular characteristicreturn signal can be distinguished by the controller 22 to verify thereis a properly qualified person at the controls. Having identifiers 38 onboth the operator 30 and on the remote controller 12 additionally allowsthe controller 22 to confirm that the operator and the remote controllerare in approximately the same location.

Referring now to FIGS. 1 and 2, the relative location of the remotecontroller 12 may be expressed in terms of (1) an approximate radialclearance R between the remote controller and an operational boundary ofthe work machine 10 and work tool 16, and (2) a location angle Smeasured with respect to a frame of reference on the machine 10—such asits longitudinal centerline 40. One skilled in the art will appreciatethat different or additional frames of reference may be necessary forsome types of work machines 10 or work tools 16. Having determinedrelative location in this manner, the information may be utilized toeffect automatic changes or restrictions in the operationalcharacteristics of the work machine 10 and/or work tool 16 based uponone or both parameters R, S. Preferably both parameters are utilized. Tofacilitate the decision-making behind such changes, the area surroundingthe work machine 10 may be divided into two or more operational sectorsor angular regions. For purposes of illustration only, the areasurrounding the work machine 10 in FIG. 2 has been divided into fouroperational sectors A, B, C, and D. Together, the operational sectorscompletely surround the machine 10 and the work tool 16. The operationalsectors extend outward to the location or potential locations of theremote controller 12. Although not shown in FIG. 2, the angular expanseof respective operational sectors A, B, C, D may be unequal andunsymmetrical. Each is pre-defined to enclose a portion, if not all, ofthe unique operational features of the work machine 10. For instance theoperational sectors A and B in FIG. 2 enclose symmetrical portions thatencompass the operational range of the work tool 16 and its positioningarm 20 and any expanded radial area between this operational range andthe present location or potential locations of the remote controller 12.Operational sectors C and D symmetrically encompass the remainingsurrounding area. For some machines a possibly more useful arrangementof these sectors would be to align them with the front, rear and sidesof the machine as shown in FIG. 3. And, for certain work tools 16 it maybe appropriate for the outer surroundings of the work tool to beencompassed by a single operational sector. For example, the latterarrangement would be suitable for a posthole auger while drilling avertical hole. As used herein, the term “outer surroundings” refers tothe area around the work machine 10 and work tool 16 not protected orobscured from the operator 30 (FIG. 1) by the machine 10 and othercomponents.

In the case of a machine 10 with a turret-mounted superstructure, suchas a compact excavator, a set of operational sectors may be aligned torotate with the superstructure while a different set of operationalsectors could be aligned with the undercarriage 14 (FIG. 1) of themachine 10. The first set of operational sectors are used while theoperator 30 is utilizing the work tool 16, while the second set ofoperational sectors are used when the machine 10 is being moved aroundthe work area. Of course, during work machine 10 movements, knowing thestowed orientation of the work tool 16 with respect to the undercarriage14 is important to insure the operator 30 is a safe distance from thework machine. The operator 30 or other worker authorized to be on thework site positioned in sectors C and D may be at risk to hazards suchas run-over or being “bumped into” when the operator is backing orturning the machine 10. Sectors A and B present similar hazards, plusadditional hazards related to actions of the movable arm 20 and the worktool 16—including any payload that may be involved.

Referring still to FIGS. 1 and 2, the location of the remote controller12 relative to the work machine 10 may be determined by reception ofsignals 42 transmitted from the constellation of GPS satellites 28 whosesignals are received by the work machine GPS receiving antenna 26 andthe remote controller GPS receiving antenna 36. Preferably an inch-levelaccuracy GPS system is utilized, such as real-time differential GPS. Oneskilled in the art will appreciate that use of a local reference station(not shown) may be necessary for the real-time differential GPS to workproperly. When converting the GPS coordinates into relative location (R,S) data, the elevation values of the resulting 3-D location coordinatesmay be ignored. To complete this conversion, the heading or orientationof the work machine 10 is determined via an on-board electronic compass(not shown), or by mounting a second GPS antenna on the work machine 10distant from the first antenna 26. Such arrangements and the equationsnecessary to transform sets of GPS coordinates into relative position(“distance away” and direction) are known by those skilled in the artand do not merit further discussion herein. In the case of a workmachine 10 with a turret-mounted superstructure, two spatially separatedGPS antennas on the superstructure and an encoder (not shown) on theturret would provide information regarding heading and configuration ofthe work machine 10. Those skilled in the art can readily determine theproper set-up for other unique machine configurations within the scopeof this invention.

“Distance away” may be converted into radial clearance R between theremote controller 12 and operational boundary of the machine 10 bysubtracting a distance equal to the radial extent of the machine 10beyond the mounting position of the GPS antenna 26 from the GPSdetermined distance. This can be accomplished through a lookup table of“work machine operational boundaries” versus relative location angle S.Some relative location angles S of the work tool 16 may be closer to theremote control operator 30 than the boundary of the work machine 10. Atany given angle S, the radial clearance R can change substantially whilethe work tool 16 is operational. For instance with a backhoe orexcavator, the work tool 16 may be moved horizontally and verticallywithin a vertical plane and this “plane of the tool” can be rotated withrespect to the machine undercarriage 14. By knowing position of the workmachine 10 in real-time and by knowing the position of the remotecontroller 12 with respect to the work machine, a real-time machineboundary can be created for the work machine. Then the machinecontroller assembly 22 automatically prevents the work tool 16 frombeing rotated or extended too close to or into the operator 30 becauseof inadvertent control actions. As the operator's control actions narrowthe radial clearance R, the operator 30 may feather his control actionsto slow the motion of the work tool 16 before completely over-riding thecontrol actions whenever a set minimum clearance R_(min) is reached forany particular location angle S of the operator. The operator 30 (orother authorized worker/observer) is then required to move away from themachine 10 to regain operational control. Alternately, the operator30—upon inputting a purposeful sequence of keystrokes (or othercommands)—could be granted temporary operational control for thosespecial circumstances where close proximity operation is necessary. Sucha circumstance could include troubleshooting the functional operation ofthe work machine 10. It will be appreciated that the principlesdescribed here also apply to converting “distance away” determined byother embodiments into radial clearance R.

Placement of encoders (not shown) or equivalent sensors at each joint ofthe work tool 16 and displacement sensors (not shown) in any telescopicfeatures related to movement of the work tool will provide informationuseful in determining the distance the work tool extends beyond the workmachine 10. This information alone or combined with determining the typeof work tool 16 installed and sensing the work machine 10 and work tooloperating conditions such as inclination or weight distribution withcommercially available operational sensors (not shown). The operationalsensors may be used to determine certain work machine and work tooloperational parameters such as speed, lift, height, or reach. For a workmachine 10 with a turret-mounted superstructure, the previouslymentioned encoder on the turret drive provides information about itsrotational movement and the associated heading of the work tool 16 withrespect to the undercarriage 14 (FIG. 1). Information from the encodersmay be processed to compute relative height of the work tool 16, itsextension in relation to a machine reference point, and (if applicable)the orientation of the above-mentioned vertical plane with respect tothe longitudinal axis of the machine's undercarriage 14. Suchcalculations for determining real-time work tool 16 position utilizingencoder information as discussed herein is known by one skilled in theart.

In the event multiple authorized personnel are present in the area ofoperation, updating their respective relative locations may benon-sequential—with priority determined by such factors as: the recenthistory of change to each particular set of location coordinates (R, S),the magnitude of the radial clearance R, and the orientation of thelocation angle S with respect to operational sectors A, B, C, D. Timelylocation information is then available to initiate, when necessary, thepreviously-mentioned automatic restrictions to the movements of the workmachine 10 and/or the operations of the work tool 16.

Turning now to FIG. 3 an alternative system for determining the positionof the operator 30 also relative to the work machine 10 is shown. In thesystem of FIG. 3, a control signal 18 (FIG. 1) is generated by atransmitter 12 carried by the operator 30. The control signal 18(FIG. 1) may comprise a radio carrier signal used to control the workmachine 10 and work tool 16. In a preferred embodiment, the transmitter12 carried by the operator 30 sends control data packets to the workmachine 10 at regular intervals. An antenna assembly 24 supported by thework machine 10 detects the control data packets and a processor in themachine controller 22 (FIG. 1) determines the position of thetransmitter 12 relative to the work machine.

The antenna assembly 24 may comprise multiple uni-directional antennassuch as a patch style antenna. As shown in FIG. 3, four uni-directionalantennas 24 a-d may be supported on the work machine 10 to divide thearea surrounding the work machine into four (4) regions: front, back,left and right. It will be appreciated that the number of regions can beincreased or decreased without departing from the spirit of theinvention. The uni-directional antenna 24 a-d receiving the strongestsignal from the transmitter 12 identifies which region the operator 30is in. The strength of the received signal may also be used to determinethe distance or radial clearance (R) between the work machine 10 and theoperator 30. In FIG. 3, the operator's position is shown somewhere alongthe dashed arc 43. Accordingly, the embodiment of FIG. 3 does notrequire pinpointing the operator's position. Rather, simply determiningwhich region the operator 30 is located in and the operator's distanceaway (r) from the work machine 10 provides sufficient information forthe machine controller 22 (FIG. 1) to make decisions, in a yet to bedescribed manner, to control or alter at least one of the operationalcharacteristics of the work machine 10 or work tool 16.

Referring now to FIG. 4, there is shown therein another embodiment of anantenna configuration of antenna assembly 24. The antenna assembly 24comprises a directional antenna assembly 44 adapted to scan an area ofoperation to determine the location of the remote controller 12 (FIG.1). Accordingly, the directional antenna assembly 44 may furthercomprise a gimble mount 46 adapted to support the directional antenna 48on the work machine 10 (FIG. 1) for movement in at least two planes.Movement of the directional antenna 48 may be automated to scan theoperational area of the work machine 10 and work tool 16 to locate theremote controller 12, any work site personnel or the operator.Alternately, the directional antenna 48 could be located at the remotecontroller 12, or directional antennas could be positioned at both thework machine 10 and remote controller.

The directional antenna 44 may comprise a gimble-mountedtransmitting/receiving antenna 48 to provide the antenna with two axesof scanning motion. The transmitting/receiving antenna 48 sends out(transmits) signals 50 along a line or narrow path that can be scannedover an area of coverage by motorized control of the gimble mounting 46.Suitable transmitting/receiving antennas 48 include a scanning laser ora directional radio antenna. In the case of a scanning laser, thetransmitted signal 50 comprises a laser beam signal 50 that is reflectedback to the scanning laser by an “identifier” such as a reflector orprism 38 (FIG. 1) mounted on the remote controller 12 or on the operator30 (or a worker and/or observer authorized to be present in the localarea around the machine 10). The automated scanning laser isfunctionally similar to a “robotic total station” surveying instrument.The motorized gimble mounting 46 scans the laser beam 50 around the workmachine 10 at differing angular trajectories until a return beam isreceived from the reflector 38 (FIG. 1). Then the directional antennaassembly 44 locks onto the reflector 38, staying in alignment with itspresent (and likely changing) position. The relative location angle S ofthe reflector 38 (thus the operator 30) with respect to the machine 10is determined from encoders on the rotation axes of the gimble mounting46. A distance away value is determined by measuring the time lapsebetween transmitted and reflected pulses of laser light—as done in alaser rangefinder or robotic total station. Again, a distance equal tothe extension of the work machine 10 (including its work tool 16) beyondthe pivotal center of the gimble mounting 46 is subtracted from thetime-lapse determined distance away value to obtain the radial clearanceR.

In a variation of the above embodiment, the reflector 38 may be replacedby an array of photo detectors comprising an “electric eye”. The photodetectors in the electric eye measure the amount of alignment offset inthe laser beam 50 and the automatic control brings the beam into properalignment by controlling horizontal and vertical drive motors of thegimble mounting 46 for the laser 50.

When starting up the remote controlled work machine 10, the remotecontrol operator 30 may input his/her present location with respect tothe work machine through a keypad (not shown) on the remote controller12. This could simply be a direction location (left, right, front,rear), or could also include an estimated radial clearance interval R(distance away from the work machine 10). Manual input of location wouldenable rapid lock-on to the position of the remote controller 12. Theoperator 30 may also “inform” the control system that one or more otherauthorized workers/observers are present on the work site.

With reference now to FIG. 5, there is shown therein an alternativeembodiment of the present invention. The embodiment shown in FIG. 5comprises a system for controlling operation of a work machine 10. Thesystem illustrated in FIG. 5 comprises a plurality of transmitters 52,54, 56 supported on the work machine 10, a remote receiver assembly 58and a processor (not shown) supported by the remote receiver assembly.The plurality of transmitters 52, 54, 56 are each adapted to transmit auniquely identifiable signal from the work machine 10. The remotereceiver assembly 58 is adapted to detect each unique signal from theplurality of transmitters 52, 54, 56. The processor is adapted todetermine a position of the remote receiver assembly 58 relative to thework machine 10 using the detected unique signals.

The system of FIG. 5 utilizes electromagnetic field signal strength toindicate distance and direction. This technique is commonly used intracking systems for determining position and below ground depth ofunderground horizontal directional drilling systems. In such trackingsystems, a beacon supported in the drilling head transmits a signal toan aboveground tracker. The beacon has at least one dipole-transmittingantenna, although other antenna arrangements are possible. Appropriatecalibration techniques relate the signal strength measured by thetracker to depth of the drilling head. This is analogous to thepreviously described “distance away” method. Here, however, one or morebeacons are mounted on the machine 10 with the axis of the dipoleantenna vertically oriented, while the tracking receiver antennas andassociated components are incorporated into the remote receiver assembly58. Preferably three or more transmitters are utilized—mounted in aspaced apart arrangement on the work machine 10, shown in FIG. 5.

Each of the transmitters 52, 54, 56 preferably transmits the uniqueelectromagnetic field at a frequency of 29 kHz or less, via a ferritecore coil antenna. Each antenna employs a sufficiently differentfrequency to allow the remote receiver assembly 58 to differentiatebetween the individual transmitters. Alternately, one frequency could beutilized when the signals are modulated with a different code for eachtransmitter to distinguish them. When three or more transmitters areutilized, the position of the remote receiver assembly 58 with respectto the work machine 10 can be uniquely determined. By inference, thisposition is also the location of the operator 30. The first step towarddefining this location involves estimating the radial distances r₁-r₃between each of the transmitters 52, 54, 56 and the remote receiverassembly 58 by performing a total field calculation on each of theirrespective signal strengths measured by the remote receiving assemblyantennas 60, 62, 64 shown in FIG. 6. Total field calculations aredescribed in U.S. Patent Application No. 60/680,780 entitled “DipoleLocator Using Multiple Measurement Points”, a commonly assignedprovisional patent application filed May 13, 2005, incorporated hereinby its reference.

Referring now to FIG. 6, the remote receiving assembly 58 may comprise atracker system, which comprises a set of three antennas 60, 62, 64 in amutually orthogonal arrangement and adapted to detect the signalstransmitted by the plurality of transmitters 52, 54, 56 (FIG. 5). Itwill be appreciated that other antenna arrangements such as a cubeantenna with multiple windings may also be suitable for application ofthe present invention. These antennas and associated tracker circuitryoperate independently from the conventional elements of the remotereceiving assembly 58. The use of three mutually orthogonal antennas 60,62, 64 allows the processor to determine the distances r₁-r₃ between theremote receiving assembly 58 and each transmitter 52, 54, 56 (FIG. 5)regardless of orientation of the remote receiving assembly 58. Thedistances r₁-r₃ are transmitted to the controller 22 for processing.Circles of radii r₁-r₃ centered on respective transmitting antennas 52,54, 56 (FIG. 5) may intersect near one common point (the operatorlocation)—as illustrated in FIG. 5. This location is then converted intolocation coordinates (R, S).

An alternative embodiment of the above system may comprise transmitterspositioned on the machine 10 in each of the operational sectors A, B, C,and D (FIG. 2). The remote receiving assembly 58 may then determine inwhich sector the receiving assembly is located by simply determiningwhich transmitter is closest (smallest r value). Distance away andapproximate location angle S are still available.

The principles of the beacon-tracker embodiment may alternately beemployed in conjunction with the actual RF carrier frequency utilized totransmit the previously described control signals 18 between the remotecontroller 12 and the work machine controller 22. The RF carrier ispreferably of a higher frequency than the frequencies of the previouslydescribed beacon transmitters. The RF carrier may be in the range from100 MHz to 50 GHz with 900 MHz being preferable. RF carrier controlsignals 18 may contain information that is decoded by the controller 22and used to control operation of the work machine 10 and work tool 16.

In any of the above embodiments, knowing whether or not the work machine10 is in motion may simplify the control logic described hereinafter.This information can be obtained in a number of different ways, forinstance by placement of encoders on the drive axles of theundercarriage 14 or through the monitoring of appropriate electricalsignals within the work machine's hydraulic control system.

In accordance with the present invention, it is desirable that thesystem know which particular work tool 16 is installed on the workmachine 10. This identification (“ID”) information may be input via akeypad or automatically through intelligent attachment. As used hereinthe term “intelligent attachment” means to automatically conform thework machine 10 to appropriate operating modes and power output of thework machine to the needs and power requirements of the work tool 16upon attachment of the work tool to the work machine. Intelligentattachment of the work tool 16 may interject a tool control system intothe control scheme of the work machine 10. This tool control system maycomprise a complex circuit with pre-wired responses based on theselected inputs from a switch bank. More preferably, the attachmentcomprises a microprocessor based control system that interfaces with themachine controller 22 to automatically alter certain operationalfunctions and power outputs of the work machine 10 to suit the needs ofthe work tool 16.

Automatic identification of the work tool 16 attached to the workmachine 10 may be accomplished through placement of an RFID tag on thework tool 16 and a corresponding reader on the machine. Each tag has aunique ID such that the reader can determine which work tool 16 isattached to the work machine 10. In a preferred embodiment, the tagreader communicates with the machine controller 22 to identify the worktool 16 attached to the work machine 10. The controller then makesdecisions based on the type of work tool 16 and its operating mode.Appropriate RFID technology is available from many sources.Alternatively, if the work tool 16 comprises electrical or hydrauliccircuits that are connected to corresponding circuits on the workmachine 10, an ID chip on the work tool 16 is configured to electricallycommunicate an ID code to the machine controller 22 when physicalconnection occurs. It will be appreciated that a purposely-designatedelectrical connection may be utilized where the work tool 16 normallyrequires only physical connection to the machine 10. In yet anothervariation, a special plug with multiple pins may be utilized. Each worktool 16 would have a unique series of missing or enabled pins, thus whenthe unit is connected the machine controller 22 could sense whichattachment is connected. Certain numbers of these pins could be shortedto certain other pins to create uniqueness. For instance, a 6-pinconnector creates well over 100 unique arrangements simply byelectrically shorting two or more pins together and sensing which if anypins are shorted. In such an arrangement, the machine controller 22polls the pin arrangement to determine the exact combination of pinconnections.

The unique ID is used to modify the operating modes of the work machine10 based upon the specific needs of the work tool 16. Additionally, thefunction of the controls of the control system may be modified tofacilitate use of the work tool 16. Operating modes associated with eachunique ID are stored in the machine controller memory module 66 (FIG.7). With reference to FIG. 1, the work tool 16 comprises the loaderbucket. An illustrative operating mode comprises use of the work machine10 and bucket 16 for picking up soil from one location and stockpilingit up at a distant location for later use. The operator 30 uses the userinput devices 34 to generate control commands used to move the unit tothe pick up location and position the bucket for pickup. The workmachine 10 and loader bucket are used in conjunction to carefully moveinto the soil and fill the bucket. Lift arms 20 and a bucket tiltcylinder (not shown) are used to quickly lift and curl the bucket in atransport position. The work machine 10 is moved to the stockpile wherethe payload is dumped by quickly raising the loader arms and uncurlingthe bucket. This cycle is repeated over and over until the work iscomplete.

In a second case the work tool 16 comprises a large diameter auger (notshown) for drilling shallow vertical holes in the soil for treeplanting. The ground drive 14 is used to properly position the auger fordrilling. Precise positioning requires careful modulation of the groundspeed and steering. The auger is not used until the machine 10 is in afixed position. An auxiliary hydraulic circuit provides power for augerrotation. Control is carefully modulated as the auger flights are slowlylowered into the soil to excavate the hole.

In yet another example, the work tool 16 may comprise a trencherconsisting of a rotating chain with teeth used to excavate the soilalong a predetermined path. Here the auxiliary circuit driving thetrencher is typically operated at a fixed speed (or hydraulic flow),typically full speed. The trencher is lowered into the soil to thedesired depth using lift arm 20. Using this work tool 16 the grounddrive circuit is carefully modulated to engage the trencher into thesoil for maximum utilization of available horsepower. Operation in thismode may continue for several hundred feet. Because this operation canbe tedious, some products such as the Ditch Witch® RT 70 tractor areequipped with an automated cruise control to make modulation and controlof the ground drive easier.

These and other examples summarized in Table 1 are included forillustrative purposes only and may not represent actual modes ofoperation. The work zone column values are essentially equivalent tominimum radial clearance R_(min) (described earlier). Aux 1 and Aux 2are power circuits that may be available on the machine 10 to providepower (typically hydraulic power) that may be necessary to operate thework tool 16.

TABLE 1 Attachment or Tool Ground Drive Arm Lift Tilt Aux 1 Aux 2 WorkZone Bucket Normal Normal Normal None None  >6 ft Sensitivity w/ (Front)max speed of 6 mph  >3 ft (Rear) Trencher Slow speed Normal Normal FullNone >10 ft sensitivity w/ Speed, (Sides and max speed of 2 mph Constantfront of when Flow Trencher) trenching. Enable Ground Drive CruiseControl Stump Nominal Sensitive Normal Full Slow >15 ft Grinder Speed,cycle Front and Constant fore & side of Flow aft Attachment Large Normal(none) Sensitive Sensitive Sensitive None  >6 ft Auger (Auger DiameterRotation) except at slow speed Cement Normal (none) Normal Normal FixedNone  >1 ft Mixer speed

Whether or not the work machine 10 is remotely controlled, automatedmode modification reduces the tedium and skill level required of theoperator 30 to modulate various controls to effectively operate eachwork tool 16. Electric and pilot operated controls are common for thetypes of machines mentioned herein. Such controls can help the operator30 with the various subtleties required for operation of the workmachine 10. However without mode modification, the operator 30 wouldhave to change the mode of operation or method in which he/she interactswith the various controls.

It should be clear that work tool identification information may beutilized to select a set of appropriately shaped and located operationalsectors A, B, C, D (FIG. 2) around the work machine 10 from apre-defined table of regions for the various work tools 16 used with aparticular work machine 10. As explained above, when the work tool is anauger, the work machine's operating modes substantially differ fromthose of a work machine 10 having a loader bucket. A work cycle of“maneuver, closely position, and drill” replaces a “load, transport,lift, dump, and return” type of work cycle.

Turning now to FIG. 7, there is shown therein a block diagram of thecontrol system of the present invention. The block diagram of FIG. 7shows the remote controller 12 and machine controller 22. The machinecontroller 22 and remote controller 12 allow the operator 30 to operatethe work machine 10 from afar much like a conventional remote control.The machine controller 22 comprises the transmitter/receiver assembly 68and controller 70. The controller 70 comprises the previously discussedprocessor 72 that receives and converts the control signals 18 (FIG. 1)into commands that cause the work machine functional operation 74 by wayof actuating various solenoid valves (not shown) and the like. Thememory module 66 is provided for storing the previously describedlook-up tables for the array of work tools 16 and associated sets ofoperational sectors (A, B, C, D) and tables of minimum radial clearanceR_(min) for all location angles S. The memory module 66 may also store ahistory of the last few results, commands, or data sets provided byother system modules 76 and 78. This information may include: the mostrecent operational commands received from the remote controller 12,operational status information, and results of calculationsperformed—such as position of the work tool 16 and location (R, S) ofthe operator 30 and any authorized workers/observers. Manual keypadinput and “automatic identifier” signals from personnel tags orintelligent work tools are also stored for present and future use.

In addition to having a table of minimum radial clearance R_(min),associated with a particular machine 10 and work tool 16 combination,the operating characteristics of the work machine and work tool may alsobe modified based upon the operator's position within a given sector (A,B, C, D.). For example, if the work tool 16 were a loader bucket, theremay be times where the operator 30 could accomplish improved operationif positioned very close to the loader bucket to observe it duringloading. This would be the situation if the work machine 10 were workingin a blind alley way. The operator 30 could not be in any other positionto watch the loader bucket load. In this situation, to preventinadvertent contact with the operator 30, machine speed might be limitedto slow movements while lift height might be limited to less than threefeet to prevent the operator 30 from being exposed to an overheadpayload. Within these limitations, the desired task could still beaccomplished.

The system shown in FIG. 7 may further comprise calculation modules 76and 78 and the directional antenna assembly 44. The tracking device 44operated under automated control of the controller 12 provides personnellocation information to the location calculation module 76. The worktool position calculation module 78 determines the current position ofthe work tool 16 and converts this into a “real-time machine boundary”for input into the operator/worker location calculation module 76. Herethe real-time machine boundary at location angle S is subtracted fromthe “distance away” data provided by the tracking device, yielding theradial clearance R. The controller 22 now allows or inhibits operatorinitiated control signals 18 on the basis of the location information(R, S) in conjunction with appropriate stored data from look-up tables,etc. in the memory module.

The work machine control system is an intelligent system that causes (orallows) a variety of possible work machine 10 and work tool 16operational responses to an operator generated control command based onthe type work tool 16 installed and the relative position of theoperator 30. For instance, shut-down of the engine (Step 1120, FIG. 8)could instead be the limitation or prevention of certain machinefunctional operations—such as disengaging the ground drive, or slowingor stopping the work tool 16. Depending upon the operator's positionrelative to the work machine 10, his/her operational command inputs viajoysticks, etc. on the remote controller 12 may be implemented by themachine controller 22 directly as received or they may be altered oreven totally circumvented to mitigate risk to one's personal safety.

The control logic of FIGS. 8 and 9 begins when the operator 30 startsthe engine of the work machine 10 at step 1000. The machine controller22 calls upon the directional antenna assembly 44 to interrogate theoperator's tag 38 (FIG. 1) and verifies the operator 30 is an authorizedoperator at step 1010. If the operator 30 is not authorized, the machinecontroller 22 shuts down the work machine engine at step 1120—or otherappropriate action is taken. The machine controller 22 (FIG. 7) thenverifies that all portions of the control system are functioningproperly at step 1020. If not, the engine is shut down. Alternatively,instead of shutting down the engine, the operator 30 may be granted“limp home” control to move the work machine 10 to a repair facility. Atstep 1030 the type of work tool 16 is determined from its identity code(or manual input). The appropriately shaped operational sectors A, B, Cand D and table of minimum radial clearance R_(min) are loaded frommemory at steps 1040 and 1050 to establish a set of work tool 16operational characteristics. The controller 22, at step 1060, calls uponthe work tool position calculation module 78 to determine the work toolposition and the real-time operational boundary of the machine 10 andwork tool. At step 1070 the directional antenna assembly 44 scans thelocal work area to locate the operator 30 and any tag wearing authorizedworkers or observers. First, the operator/worker location calculationmodule 76 determines whether the operator is positioned a properdistance R from the machine 10 and its work tool 16 (Steps 1070-1090).If the operator 30 and thus the remote controller 12 or ID tag 38 arewithin the operational boundary of the work tool 16 and work machine 10(i.e., R≦R_(min)), the operator is notified by a warning light or soundactivated at the remote controller 12 and certain pre-designated machinefunctions are disabled or able to function only at a reduced level. Theoperator 30 is given an amount of time T to move to a favorable location(i.e., R>R_(min)) in the loop 1110, 1090, 1100 or the engine willshut-down at 1120. Time “T” is set to zero ahead of this loop, at step1080. Alternatively, the machine controller 22 may allow only minimalfunction or no function of the work machine 10 and work tool 16 untilthe operator 30 is outside the operational boundary defined by R_(min).

If the operator 30 moves into or is already in a favorable location(i.e., R>R_(min)), the control logic moves to 1300 shown in FIG. 9.Here, at step 1510, the directional antenna assembly 44 is interrogatedby the controller 22 to determine the presence of other authorizedworkers or observers. Alternately, the operator 30 may manually entertheir presence and number at step 1500. If no workers or observers arepresent, the full range of machine functions subject to the controlparameters stored in the memory module 66 (FIG. 7) are enabled at step1520 and program control repeatedly cycles back through an updating loopby returning to 1200 (FIG. 8). When worker or observers are present, thescanning directional antenna assembly 44 is called upon to obtain theircharacteristic identities at step 1530. Their location relative to thework machine 10 may already be known from the determination at step1070. At steps 1540-1550 the operator/worker location calculation module76 determines whether each of the workers or operators are positioned aproper distance R from the real-time operational boundary of the machine10. If so, all machine functions are enabled at step 1520. If not, time“T” is set to zero at step 1560 and program control reverts to step 1400(FIG. 8) where operation of certain machine functions may be inhibited.The operator 30 is made aware of the intrusion and given time “T” tocorrect it—or the engine shuts down (or certain operational functionsare temporarily reduced until the intrusion is corrected). In this way,the operator 30 and tag wearing authorized worker or observer areprevented from being too close to an operating work machine 10.

The present invention also comprises a method for controlling operationof a work machine 10 comprising a plurality of operationalcharacteristics. Control of the work machine 10 may be based, in part,on the location of the operator 30 relative to the work machine and thetype of work tool 16 attached to the work machine. In a preferredmethod, a control signal 18 is generated by a remote controller 12 at alocation remote from the work machine 10. The control signal 18 isdetected at the work machine 10 by one of the receiving assembliesdescribed herein. The machine controller 22, supported on the machine10, processes the control signal 18 to determine the point of origin ofthe control signal relative to the work machine. After determining thepoint of origin of the control signal 18 and thus the location of theoperator, the controller 22 controls or alters at least one of theplurality of operational characteristics of the work machine 10 or worktool 16 based upon the control signal 18 and the determined point oforigin of the control signal. In accordance with the present invention,the method may further comprise establishing an operational boundarydefined by the type of work tool 16 and the configuration of the workmachine 10. In such cases, the operational characteristics, i.e. theallowed movements of the work tool 16 and work machine 10, may bemodified based upon the location of the remote controller 12 or anobserver within the machines operational boundary.

Still yet, the present invention includes a method for controllingoperation of a work machine 10 having a plurality of machine signaltransmitters supported on the work machine. The plurality of machinesignals are detected at the receiver assembly 58. A processor supportedby the receiver assembly 58 processes the detected machine signals todetermine the location of the receiver assembly relative to the workmachine 10. Alternatively, the distance determined from each machinetransmitter 52, 54, 56 could be transmitted back to the machine 10 forprocessing by the machine controller 22. The machine controller 22 thenmay perform calculations to determine the operator's position relativeto the work machine 10. Having the processor on the machine 10 reducesthe power needed by the remote controller, thus conserving battery life.This alternative method provides equivalent data reliability with lesspower consumption. The receiver assembly 58 then transmits a controlsignal 18 from the receiver assembly to the work machine 10. The controlsignal 18 is processed by the machine controller 22 and used to controlor alter an operational characteristic of the work machine 10 based uponthe determined location of the receiver assembly 58 relative to the workmachine 10. This method may also include establishing at least twooperational sectors defined by the work machine 10 and the work tool 16.Work machine 10 and work tool 16 functions are then controlled by theremote controller 58 based upon the location of the either the operator30 or workers and observers within certain of the operational sectors,as described above.

Various modifications can be made in the design and operation of thepresent invention without departing from the spirit thereof. Thus, whilethe principal preferred construction and modes of operation of theinvention have been explained in what is now considered to represent itsbest embodiments, which have been illustrated and described, it shouldbe understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically illustratedand described.

What is claimed is:
 1. A method for controlling a work machinecomprising at least one of a plurality of different types of work toolsand a machine controller, the method comprising: operatively connectingthe at least one of the plurality of different types of work tools tothe work machine; determining a type of work tool operatively connectedto the work machine from the plurality of different types of work tools;determining a location of a remote control system relative the workmachine; loading onto the machine controller operational characteristicsof the work machine and operational characteristics of the at least oneof the plurality of different types of work tools based upon the type ofwork tool operatively connected to the work machine; establishing anoperational boundary defined by the location of the remote controlsystem, the type of work tool, and configuration of the work machine;wherein the operational boundary automatically changes based uponmovement of the work machine and the location of the remote controlsystem; determining a location of a person relative to the operationalboundary; and automatically altering at least one of the operationalcharacteristics using the machine controller based upon the location ofthe person relative to the operational boundary.
 2. The method of claim1 further comprising altering the at least one of the operationalcharacteristic of the at least one of the plurality of different typesof work tools if the person is inside the operational boundary.
 3. Themethod of claim 1 further comprising transmitting a control signal fromthe remote control system to operate the at least one of the pluralityof different types of work tools subject to the loaded operationalcharacteristics.
 4. The method of claim 1 wherein the operationalboundary comprises a plurality of operational sectors and wherein themethod further comprises changing at least one of the operationalcharacteristics based upon the location of the person within aparticular one of the plurality of operational sectors.
 5. The method ofclaim 1 further comprising determining an operating condition of thework machine and further altering one or more operationalcharacteristics of the at least one of the plurality of different typesof work tools based upon the operating condition of the work machine. 6.The method of claim 5 wherein determining the operating condition of thework machine comprises sensing an inclination of the work machine. 7.The method of claim 1 wherein altering the operational characteristic ofthe at least one of the plurality of different types of work toolscomprises limiting a range of movement of the work tool based upon thelocation of the person within the operational boundary.
 8. The method ofclaim 1 wherein altering the operational characteristic of the workmachine comprises limiting a rate of movement of the work machine. 9.The method of claim 1 further comprising sensing movement of the atleast one of the plurality of different types of work tools and furtheraltering at least one of the operational characteristics in response tothe sensed movements of the at least one of the plurality of differenttypes of work tools and the location of the person relative to theoperational boundary.